Abdul Wadood ( Department of Pharmacology and Therapeutics, khyber Medical College, Peshawar. )
Noreen Wadood ( Department of Pharmacology and Therapeutics, khyber Medical College, Peshawar. )
S. A. Wahid Shah ( Department of Pharmacology and Therapeutics, khyber Medical College, Peshawar. )
The powdered seeds of Acacla arabica and roots of Caralluma edulis were administered in doses of 2, 3 and 4 gm/kg body-weight to normal and alloxan-diabetic rabbits. The blood glucose levels were estimated before and 2, 4, 6 and 8 hours after the administration of plant suspension. The powdered seeds of Acacla Arabica exerted a significant (P <0.05) hypoglycemic effect in normal rabbits. The hypoglycemic effect was not significant (P >0.01) in alloxan diabetic rabbits. The powdered roots of Caralluma edulls did not produce any significant (P >0.01) hypoglycaemic effect in normal as well as in alloxan diabetic rabbits. The doses used did not show any acute toxicity and behavioural changes. From this study it may be concluded that the powdered seeds of Acacia arabica act by initiating the release of insulin from pancreatic beta cells of normal rabbits. Moreover, Caralluma normal as well as in diabetic rabbits (JPMA 39:208,1989).
Many indigenous remedies have been traditionally used in the treatment of a variety of diseases including diabetes mellitus1. Several such plants show hypoglycaemic activity when taken orally, for example Coriandrum sativum, Dacucus carota, Brassica oleracea, Cassia occidentails, Olea europea and Zingiber officenale2. Said3, Farsworth and Scgelman4 and Ikram5 have reported the anti-diabetic activity of a number of herbs and plants, amongst these, Acacia arabica and Caralluma edulis, locally known as "Kikar" and “Chung” respectively, have been used by practitioners of Asian system of medicine for the treatment of diabetes mellitus6. Acacia arabica belongs to the family Leguminosae. This tree, found all over the subcontinent9 yields an abundant supply of gum. The decoction of its bark is used in diarrhoea, dysentery and gargles for spongy gums. The bark is astringent and is used as a tan10. The powdered seeds have been found useful in the treatment of diabetes mel- litus6,8. Caralluma edulis belongs to the familyAsclepiadeae. Its bitter stem and roots are used as vegetables. Its roots are used in the treatment of diabetes mellitus10. The present work has been undertaken with the aim to study the effect of powdered seeds of Acacia arabica and powdered roots Caralluina edulis on the blood glucose levels of normal and alloxan diabetic rabbits. Acute toxicity and behavioural changes were also studied to check the safety of these doses.
MATERIAL AND METHODS
Experiments were performed on male, adult rabbits of local strain weighing 0.65-1.82 kg. They were fed on green vegetables and grains and allowed tap-water ad libitum.
Alloxan monohydrate was supplied by B.D.H. Laboratories (Chemical Division), Poole, England. Otolodine, Glacial acetic acid, Thiourea and Thchloroacetic acid were obtained from E. Merck, Dermstadt, West Germany. Tolbutaniide was provided by Hoechst, West Germany.
The seeds of Acacia arabica were obtained from local trees of University Campus. The fresh roots of Caralluma edulis were purchased from local vegetable market of Peshawar. They were carefullywashed with water to remove dust and any otherforeign material and dried under the shade. The completely dried seeds of Acacia Arabica and roots of Caralluma edulis were powdered with an electric grinder and stored in cellophane bags at 4°C in the refrigerator.
Preparation of Diabetic Rabbits
Using Akhtar et al11 method a group of rabbits were made diabetic by injecting intravenously, 150mg/kg body weight of alloxan monohydrate. Eight days after injection, the blood glucose levels of surviving rabbits were estimated. Rabbits with blood glucose levels above 200mg/lOOm! were considered as diabetic.
Grouping of Rabbits
Normal rabbits were divided into 5 groups of six animals each. Group 1 served as control and received 15m1 of 2% gum tragacanth solution. Group 2 received tolbutamide 500mg/kg body weight. Group 3-5 received dried powdered seeds of Acacia arabica dissolved in 15ml of 2mg/kg, 3gm/kg and 4gm/kg respectively. The diabetic rabbits were also divided in 5 groups on the same pat tern. Similar to above, S groups of six rabbits each were made to study the effects of powdered roots of Caralluma edulis. Group 1 served as control received 15ml of 2% gum tragacanth solution. Group 2 received tolbutamide 500mg/kg body weight. Group 3-5 received dried powdered roots of Caralluma edulis dissolved in 15ml of 2% gum tragacanth solution in doses of 2gm/kg, 3gm/kg and 4gm/kg respectively. The diabetic rabbits were also divided inS groups on the same pattern.
Preparation and Administration of Plant Suspension
The amount of powdered seeds of Acacia arabica and powdered roots of Caralluina edulis required for each rabbit was calculated on body weight basis and it was dissolved in lOmlof 2% gum tragacanth solution and fmal volume made upto 15ml. The suspension was administered to each rabbit by using a stomach tube attached to a standard syringe containing the 15ml of the suspension. The tube was inserted into the stomach through oesophagus and the plunger was pressed slowly and steadily. Immediate sneezing and coughing indicated injection into the lungs and in such a condition tube was at once withdrawn and another animal was takeninstead. The tolbutainide solution was administered in a similar manner.
Collection of Blood
The procedure for collection of blood was adopted as described byAkhtar and Ali12. The rabbit was held in a wooden rabbit holder and immediately before administration of drug, 0.2ml of blood for glucose estimation was collected from an ear vein. Similar blood samples were collected at 2,4,6 and 8 hours after the administration of drug. After collection of blood the pricked site of the ear was rubbed with cotton wool soaked with 70% alcohol to protect the rabbit against infections.
Blood Glucose Estimation
Blood glucose estimation was done by the method of Winckers and Jacobs13.
Acute Toxicity Studies
The possible toxic effects of the powdered seeds of Acacia arabica and powdered roots of Caralluma edulis were studied on rabbits of local strain weighing 0.50-1.71kg. The rabbits were divided into 4 groups (1-4) of six animals each. Group 1 served as control and received 15ml of 2% gum tragacanth solution. Group 2-4 received powdered seeds of Acacia arabica dissolved in 15ml of 2% gum tragacanth solution in doses of 2gm/kg, 3gm/kg and 4gm/kg respectively. Animals were observed for 8 hours after the administration of plant suspension to check toxic symptoms. They were kept under observation for 7 days. Similar to above, 4 groups of six animals were made to study the possible toxic effects of Caralluma edulis.
The effects of different doses of Acacia arabica, Caralluma edulis, tolbutamide and gum tragacanth on blood glucose levels of normal and alloxan-diabetic rabbits are shown in Table I,II and figure I,II.
The mean percent decrease in blood glucose levels produced by 2gm/kg of Acacia arabica at 2,4,6 and 8 hours were 10.0±0.58, 13.3±0.35, 15.0±0.76 and 11.6±0.97 respectively while those produced by 3gm/kg of Acacia arabica at similar interval were 16.51±0.68, 22.93±0.97, 26.14±1.08 and 24.22±23 respectively and that produced by 4gm/kg of Acacia arabica at 2,4,6 and 8 hours were 28.1±0.71, 34.4±0.56, 40.6±1.65 and 38.85±1.1 respectively. All the three doses showed significant reduction (P <0.05) in blood glucose levels. The mean percent decrease in blood glucose levelsproducedby2gm/kgofCaralluma edulis at2, 4, 6 and 8 hours were 0.57±0.05, 0.38±0.06, 0.19±0.01 and 0.28±0.03 respectively while that produced by 3 gm/kg of Caralluma edulis at similar intervals were 0.49±0.1,0.90±0.08,1,17±0.05 and 0.68±0.09 respectively and that produced by 4gm/kg of Carallunia edulis at 2, 4, 6 and 8 hours were 020 ± 0.07,0.40± 0.02,0.90± 0.05 and 0.50 ± 0.04 respectively. All the doses showed no significant change in the reduction of blood glucose levels. The mean percent decrease in blood glucose levels produced by 500mg/kg of tolbutamide at 2,4,6 and 8 hours were 14.19±0.75, 28.29±1.2, 24.45±1.7 and 2353±0.92 respectively, (significant P <0.05) while that produced by 15ml of 2% gum tragacanth solution at 2,4,6 and 8 hours were 121 ± 0.11, 1.72 ± 0.13, 1.51 ± 0.10 and 0.29 ± 0.05 respectively (not-significant P >0.10). With Acacia arabica the mean percent decrease in blood glucose levels at 2, 4, 6 and 8 hourswere 0.49 ± 0.07,121± 0.03,1.61±0.08 and 1.52 ± 0.09 respectively, with 2gm/kg dose and 0.93±0.04,1.34±0.07,1.51 ± 0.06 and 1.10 ±0.09 respectively, with 3gm/kg and 0.45 ± 0.06, 1.17 ± 0.03, 1.56 ± 0.02 and 1.21 ± 0.06 respectively with 4gm/kg dose. All the results showed no significant. reduction in blood glucose levels. With Caralluma edulis the mean percent decrease in blood glucose levels at 2,4,6 and 8 hours were 1.32 ± 0.06, 1.37 ± 0.09,2.33 ± 0.85 and 1.76 ± 0.76 respectively with 2gm/kg dose and 0.68 ± 0.05, 1.13 ± 0.07, 1.63 ± 0.05 and 0.94 ± 0.08 respectively with 3gm/kg and 027 ± 0.03, 0.50 ± 0.05,0.70 ± 0.07 and 0.40 ± 0.01 respectively with 4gm/kg dose. All the results were not significant. The mean percent decrease in blood glucose levels produced by 500mg/kg of tolbutamide at 2,4, 6 and 8 hours were 022 ± 0,03,0.43 ± 0.01, 0.49 ± 0.87 and 0.61 ± 0.13 respectively (not-significant) while that with 15ml of 2% gum tragacanth solution similar interval wereO.50 ± 0.07,1,03 ± 0.05,1.17 ± 0.91 and 0.81 ± 0.06 respectively, (not-significant). Acute Toxicity Study The rabbits receiving 2gm/kg, 3gm/kg and 4gm/kg of powdered suspension of Acacia arabica and Caralluma edulis did not show any visible signs of toxicity e.g. excitement, restlessness, respiratory distress, convulsions or coma. Moreover, they re mained alive for upto 7 days.
The present study showed that the gum tragacanth solution used as vehicle did not produce any significant (P >0.01) change on blood glucose levels of normal and on alloxan induced diabetic rabbits. This finding is in accordance with the observations of Marquis et al14 and Akhtar et al15. It was also observed that powdered seeds of Acacia arabica produced a significant hypoglycaemic effect when administered orally to nor-mal rabbits. While its seeds in dose of 4gm/kg produced a maximum decrease in blood glucose levels of normal rabbits. The observations also indicate that hypoglycaeniic effect in normal rabbits develops slowly and is most pronounced about 6 hours after the administration. The seeds of Acacia arabica, however, did not show any significant effect on blood glucose levels of alloxan-treated rabbits. For comparison the effect of the standard hypoglycaemic drug tolbutamide (500mg/kg) was observed on the blood glucose levels of normal and alloxan treated diabetic rabbits. Tolbutamide produced significant hypoglycaemic effect in normal rabbits but not in alloxan-treated rabbits. This finding is in accordance with the observation of Augusti and Benaim16 and Akhtar et al17. Sulphonylureas including tolbutamide have been reported to produce hypoglycaemia by stimulating pancreatic fi cells to release more insulin into the blood stream, thus increasing glycogen desposition in the liver, causing a reduction of glycogen levels, and having an extra pancreatic effect to possibly increase the number of insulin receptors18. In view of the similarity between the effect of toibutamide and Acacia arabica, it may be likely that the hypoglycaemic effect of Acacia arabica also be mediated through the release of insulin from the pancreatic beta cells. A similar mechanism has been proposed to explain the hypoglycaemic effect in normal rabbits of other indigenous plants such as Thcoma Stans19, Momordica Foetida14 Euphorbia prostrata and Fumaria Parviflora15. Eriobotria Japonica20 and Gymnema Sylvestre21,22.The observations show that the roots of Caralluma edulis did not produce any significant hypoglycaemic effect in normal or in alloxan treated diabetic rabbits. This indicates that Caral luma edulis is devoid of antidiabetic activity but is traditionally used only on empirical grounds in the folk medicine.
(Senior Technician), Jamil Khan (Technician) for technical help. Thanks are also due to Mr. Abdur Rashid Azad Artist, who gave skillful help in the preparation of figures. Authors are also grateful to Mr. Burbanuddin for typing this manuscript.
1. Hamid, A.K. and Burney, A. A preliminary study of the hypoglycaernic properties of indigenous plants. Pakistan J. Med. Res., 1962; 2: 100.
2. Lewis, H.W. and Elvin Lewis, M.P.H. Plant affecting man’s health. Medical Botany, New York, Willey, 1977, P.218.
3. Said, H.M. Hamdard Pharmacopoea of eastern medicine Karachi, Hamdard National Foundation, 1970, P.53.
4. Farnsworth, M.R. and Segelman, A.B. Hypoglycaemic plants, Tile. Till., 1971; 57:52.
5. Ikram, M. and Hussain, S.F. Compendium of Medicinal Plants. Peshawar, Pakistan Coun. Sci. and Indus. Res., 1978, p.7.
6. Nadkarni, KM. Indian materia medica. 3rd ed. Bombay, Popular Book Depot, 1954; p. 10.
7. Singh, K.N., Chandra, V. and Barthwal, K.C. Letter to the editor: Hypoglycaemic activity of Acacia arabica, Acacia benthami and Acacia modesta leguminous seed diets in normal young albino rats. Indian J. Physiol. Pharmacol., 1975; 19:167.
8. Zaman, M.B. and Shariq, M.K. Hundred drug plants of West Pakistan, Islamabad. Printing Corporation of Pakistan Press, 1970, P.3.
9. Said, H.M. Pharmacographia indica. Karachi Hamdard National Foundation, 1972; P. 146.
10. Anonymous. A note on the plants of medicinal value found in Pakistan, Islamabad. Printing Corporation of Pakistan Press, 1984, P.1.
11. Akhtar, M.S., Athar, M.A. and Yaqub, M. Effect of Momordica charantia on blood glucose levels of normal and alloxan diabetic rabbits. Planta Med., 1981; 42:205.
12. Akhtar, M.S. and All, M.R. Study of hypoglycaenfic activity of Cuminum nigrum seeds in normal and alloxan diabetic rabbits. Planta Med., 1985; 51:81.
13. Varley, H., Gowenlock, A.H. and Bell, M. Blood glucose and its determination, in practical clinical biochemistry. 5th ed. London, Heinemann, 1980, p. 396.
14. Marquis, V.0., Andanlaw, T.A. and Olaniyi, A. A. The effect of foetidin from Momordica foetida on blood glucose levels of albino rats. Planta Med., 1977; 31:367.
15. Akhtar, M.S., Khan, Q.M. and Khaliq, T. Effect of Euphorbia prostrata and Fumaria parvifloria in nor moglycaemic and alloxan- treated hyperglycaemic rabbits. Planta Med., 1984; 66: 138.
16. Augusti, K.T. and Benaim, M.E. Effect of essential oil of Onion (APDS) on blood glucose, free fatty acids and insulin levels of normal subjects. Clin. Chim. Acta., 1975;60:121.
17. Akhtar, M.S., Khan, Q.M. and Khaliq, T. Effect of Putulaca Oleracae (Kulfa) and Taraxacum officinale (Dhudhal)innormoglycaemicand alloxan treated hyperglycaemic rabbits. JPMA., 35: 207.
18. Karam, J.H. Pancreatic harmones and antidiabetic drugs in Basic and Clinical Pharmacology by Bertram G. Kat zung, Maruzen Asian ed. Singapore, Huntsmen off-set, 1982, p.458.
19. Nash, J.B., Albeit, C.C., Howard, J.K and Fly, S.H. Jr. Lack of antidiabetogenic and antidiabetic effects of Tecoma stans in alloxan diabetes. Tex. Rep. Biol. Med., 1950; 8 : 350.
20. Noreen, W., Wadood, A., Hidayat, H.K. and Wahid, S.A.W. Effect of Eribotria Japonica on blood glucose levels of normal and alloxan diabetic rabbits. Planta Med., 1988; 3: 196.
21. Wadood, A. and Hidayat, H.K. A comparative study of effects of Gymnema sylvestre extract, tolbutamide and metformin on blood glucose levels of normoglycaemic and hypcrglycaemic rabbits. Pakistan J. Med. Res., 1987;26:71.
22. Iftikhar, A.D., Mohammad, A. and Yaqub, M. Effect of Grewia asciatica, Gossypium perbacium and Gymnema sylvestre on blood glucose, cholesterol and triglyceride levels in normoglycaemic and alloxan diabetic rabbits. JPMA., 1988; 38: 389.